You want at least two weeks of shelf stable/frozen food that is hopefully the things you would normally eat. Same for your pets. Any medication you use (whether OTC or prescription) would be a good idea to stock up on. It might not be a bad idea to have on hand any cold/flu medication you would normally take. A box of disposable rubber gloves would be a good idea, as would sufficient stores of anything else you routinely use (toiletries, paper towels, TP, cleaning products, booze, etc.). Hand sanitizer isn't a bad idea although it is unclear how effective it is on the WuFlu. If you can find Hibiclens locally or on line it definitely will kill pretty much anything.
If this is all stuff you will buy/use anyway, I would go ahead and get a month's worth. The cost is trivial for most board members and, like I said, you will use it anyway.
It doesn't matter whether or not masks work because they are pretty much unobtanium at this point.